Mobile terminals (or electronic devices) may be configured to perform various functions, for example, data and voice communication, capturing images or video, storing voice, reproducing music files via a speaker system, displaying images or video and the like. Some mobile terminals may include an additional function of playing games, and other mobile terminals may be implemented as multimedia players. In addition, recent mobile terminals can receive broadcast or multicast signals to allow viewing of video or television programs.
Furthermore, many efforts are underway to support or enhance various functions of such mobile terminals. Such efforts include not only changes and improvement of structural components for implementing a mobile terminal but also software or hardware improvement.
Among other functions, a touch function of the mobile terminal is designed to aid a user who is unfamiliar with button/key input using a touch screen to conveniently execute operations of the mobile terminal. Recently, the touch function is becoming an important function of the terminal together with a user interface (UI), in addition to a simple input function. Hence, as the touch function is further implemented in the mobile terminal in various forms, development of appropriate UIs is needed to a larger extent.
Recently, mobile terminals are evolving to display Three-Dimensional (3D) images allowing for depth perception and stereovision beyond levels corresponding to display of Two-Dimensional (2D) images, and related products are being released. This allows users to experience more realistic 3D stereoscopic images using a mobile terminal having a 3D imaging function, and to use various user interfaces or contents related to the 3D stereoscopic images.
When a user watches a 3D image using a mobile terminal, a depth of the image is fixed to a default value. This causes limitations on expressing the sense of dimension (stereoscopic effect) for each object of the image. Accordingly, the user has to watch the 3D image with the same depth irrespective of the surrounding environment, including, in particular, ambient brightness (quantity of light). However, the depth that the user senses may depend on ambient brightness and screen brightness even if the image has a fixed depth. When such a situation continues for a long (or extended) period of time, the user may experience considerable fatigue.
The related art has not provided satisfactory user interfaces (UIs) for adjusting the depth of a 3D image in order to reduce eye strain under such situations.